Evaluation of the Central Nervous System

Question 1

What is the lumbar puncture (LP) useful for?

Answer 1

It’s helpful to obtain the cerebrospinal fluid (CSF); making it useful to diagnose:

• meningitis
• encephalitis
• subarachnoid hemorrhage

Question 2

Define meningtitis

Answer 2

Inflammation in the subarachnoid space

Question 3

What Sx triad occurs in meningitis?

Answer 3

nuchal rigidity, mental status change, and fever

Question 4

What is the clinical utility for CSF gram stain and culture?

Answer 4

It’s helpful for the rapid and accurate diagnosis for bacterial meningitis
- takes 24-48 hrs for the results to come in

Question 5

Should antibiotics be given to patients before cultures are taken?

Answer 5

No, because it could decrease the likelihood of isolating pathogen

Question 6

Would a gram stain show up positive or negative for viral/fungal meningitis?

Answer 6

Negative

Question 7

What is the purpose for polymerase chain reaction (PCR)?

Answer 7

Its main use is to diagnose viral CNS infection

- Has a high sensitivity and specificity

Question 8

Who am I?

Used to obtain CSF; can assess opening pressure; Safety: cerebral herniation

Answer 8

Lumbar puncture

Question 9

What is electroencephalography’s function?

Answer 9

Monitors the electrical activity of the brain

Question 10

What is 1 of the clinical utilities for electroencephalography (EEG)?

Answer 10

to differentiate seizures

Question 11

What is electromyography’s (EMG) function?

Answer 11

To measure muscle activity in response to nerve stimulation

Question 12

What is 1 of the clinical utilities for EMG?

Answer 12

To identify muscle disease

Question 13

What is the nerve conduction velocities (NCVs) function?

Answer 13

To measure nerve stimulation

To detect the presence of localized peripheral nerve injuries

Question 14

What are the 2 clinical utilities for NCVs?

Answer 14

To identify carpal tunnel syndrome/myasthenia gravis

To safely have a low-risk; pacemaker - modify electrode position

Question 15

Who am I?

Used to assess electrical activity of the brain; can differentiate seizure etiology; safety: noninvasive, low risk

Answer 15

Electroencephalography (EEG)

Question 16

What is the function of a computed tomography (CT)?

Answer 16

It combines serial X-rays via computer processing

It’s essentially used in focal neurologic findings

Question 17

What are 2 important clinical utilities in a CT?

Answer 17

To differentiate cerebral infarction vs. hemorrhage

It’s negative/positive outcomes: risk of radiation (+), and some contrast

Question 18

What is the function of a magnetic resonance imaging (MRI)?

Answer 18

It uses magnetic properties of the Hydrogen atom

• Has improved anatomic accuracy compared to CT
• It might be ineligible for patients with metal implants

Question 19

What is 1 clinical utility for MRIs?

Answer 19

It’s positive (safe) outcome is it has a low risk of radiation (-)

Question 20

What is the function of a Magnetic Resonance Angiography (MRA)?

Answer 20

Same function as MRI

• HOWEVER, it’s essentially used in cerebral circulatory evaluation, such as:
• • Intracranial disease

Question 21

Who am I?
Used to assess status of the cerebral vasculature, identify intracranial disease; Safety: (-) radiation risk, (~) contrast

Answer 21

Magnetic Resonance Angiography (MRA)

Question 22

What is a Positron Emission Topography’s (PET) function?

Answer 22

To assess regional metabolic changes in the brain

- Essentially used for Extracranial metastatic disease

Question 23

What is 1 clinical utility for PET scans?

Answer 23

To identify Alzheimer’s disease

Question 24

What is the function of a Single-Photon Emission Computed Tomography (SPECT)?

Answer 24

To uptake radionucleotide (e.g., radiotracer)

Question 25

What is 1 clinical utility for a SPECT scan?

Answer 25

To identify cerebral ischemia and dementia